Cosmetic brush



FIG. 1 is a top view of cosmetic brush, showing our new design;

FIG. 2 is a greatly reduced perspective view thereof;

FIG. 3 is an enlarged detailed perspective view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a reduced left side view thereof; and,

FIG. 6 is a reduced right side view thereof.

The ornamental design for a cosmetic brush, as shown and described.